The present invention relates generally to improvements in container closures and it relates particularly to an improved screw or twist type closure cap for bottles, jars and the like.
Bottles, jars and other containers are conventionally provided with twist type closures usually in the form of metal caps having a helical ridge or recess formed in the inside face of its cylindrical wall to permit the tightening and loosening of the closure attendant to the sealing or opening of the bottle or jar. In as much as the container should be tightly sealed by the closure to protect the container contents against contamination and exposure to the ambient atmosphere it is often difficult to manually twist the closure cap to separate it from the container or to effect a reliable seal. This is due to the slippage between the operator's finger or hand and the peripheral surface of the closure which at best has a low friction coefficient or has sharp projections which may cause injury to the person. The conventional twist type closure cap possesses additional drawbacks and has much to be desired.